The number of vulnerabilities found in Microsoft's Windows 7 and XP operating systems doubled last year over 2012, with the highest number of flaws reported in Windows 8, according to new research from Secunia.

The Denmark-based security company said 102 vulnerabilities were found in Windows 7 in 2013 and 99 in XP, up from 50 and 49 vulnerabilities respectively in 2012.

Windows 8 had the most vulnerabilities, at 156, but Secunia said that was due to the integration of Adobe System's Flash Player into the Internet Explorer browser, which accounted for 55 of those problems.

Secunia released the data in its annual report on software vulnerabilities, which looks at the 50 most commonly used programs and operating systems.

Microsoft took the first three spots in the list with its XML Core Services, followed by Windows Media Player and Internet Explorer. Adobe came in fifth place with its Flash Player and seventh place with Reader. Oracle occupied the number ten spot with its Java platform.

Eighty-six percent of the vulnerabilities found in the top 50 software products had a patch available on the day the vulnerability was disclosed, Secunia said. Administrators typically want to patch quickly to thwart attacks.

The report noted that the gap in time between when a flaw is identified and when a patch is ready continues to improve, showing that "researchers are continuing to coordinate their vulnerability reports with vendors and vulnerability programs, resulting in immediate availability of patches for the majority of cases."

Third party programs, which are made by a variety of vendors, contained about 76 percent of the vulnerabilities in the top 50 programs in 2013. That's down from 86 percent in 2012, but "highlights the difficulties faced by end users and administrators in keeping their systems secure," according to the report.

"Each vendor has its own security update mechanisms and varying degrees of focus on security," Secunia said. "This represents a(major challenge to the users of personal computers and administrators of IT infrastructures, because not all vendors offer automated update services and push security updates to their users."

Secunia found only 10 zero-day vulnerabilities, which are those actively being exploited that don't have a patch, in its top 50 portfolio.